Rough skin

For the past couple of days I have noticed that my daughters diaper area and tummy that us under the diaper feels king of rough and it goes all the way to her back that is also under the diaper. Her skin is not red and it Dosent seem to bother her.... Any suggestions as to what this could be?

Grace's did that for awhile, too. It was mostly during the day then at night it would get soft again.. Almost like her skin was protecting itself from getting a rash from the diaper when she started wiggling instead of just laying there.